Mechanical tools

  Colouring of metals . methods of colouring by heat .different methods of colouring metals . method of blackening /black oil finishing of metal surfaces Machined or filled ferrous metal  surfaces can be colored by the following methods. Heating and cooling Application of chemicals Colouring by heating Attractive colours can be given to metals by  heating. In this process, the metal surface to be treated is thoroughly polished. The metal is then placed in a heat treatment oven or flame heated. During the heating of the metal, watch the colours as they appear. When the desired colour is seen, remove and quench suddenly in water or oil. Rub gently with steel wool. Black oil finish For blackening the surface of a ferrous metal, first clean the surface thoroughly, and apply a coating of thick lubricating oil. Then heat the metal to 150° to 175° c for about 5 to 8 minutes. This will give a black and rust preventing coating on ferrous metal surfaces. Chemical colouring Polished...

. different angles formed at the cutting edge of tools . the important of clearance and rake angles in metal cutting Metal cutting Knowledge about the principal for metal cutting relating to the various tool angles will assist in carrying out of metal cutting work efficiently. Workpiece are shaped and brought to the required dimension by the use of cutting tools. While cutting materials the following four important elements interact. Cutting tool Tools holding or grinding device Work holding devices, and work Although the metal cutting process involves the combination of the above four elements, everything begins with a cutting tool and its impact at the time of contacting the workpiece. The common metal cutting processes are carried out either by the  use of a single point or multi point cutting tools. Cutting edge are taken as the factors for determining the tool life, surface finish, and the force required for cutting. The important angles of the cutting edge are Clearance angle...

Different types of cutting saws Advantages of a horizontal band saw Different types of cutting saws Metal cutting saws of different types are used in industries. The most commonly used are the Power saw Horizontal band saw circular saw Contour saw Power saw This is the most commonly used metal cutting saw. Horizontal band saw This has a saw frame on which a motor is  fitted. There are two pulley wheeels on which an endless band saw passes. Speed variation is obtained through the stepped pulleys on the motor. The roller guide brackets provides the rigidity for the blade in the cutting area and also prevent wandering of the blade while cutting. The blade tension is maintained by using the adjusting handle, provided for this purpose. A vice is provided for holding the metal stocks. The vice is adjustable for angular cutting. The machine has the advantage of continuous cutting ability, and is much faster than a power saw. It may be noted that a power saw cuts only in every alternate st...

Features of power hacksaw features of a power hacksaw . correct blade of different types . features of power hacksaw blade Cut-off saws are used to cut metal stock roughly to the required length. 🤺 commonly used to cut off saw in small scale industries is a POWER SAW. Power hacksaw Features The power saw works like a handsaw, and has an arrangement for cutting during the movement in one direction and releasing pressure on the non-cutting stroke. The rotary motion of the motor is converted into linear motion by a crank mechanism. The required cutting pressure is obtained hydraulically or by an adjustable weight. During the non-cutting motion the blade will be lifted away from the work. A clamping device /vice holds the work firmly. Power hacksaw blades The saw blades are selected, depending on the machine and the type of work on hand. The blades are made of H. S. Steel and are fully hardened. For different materials, blades of different pitches are used (number of teeth per 25mm length...

. parts of a telescopic gauge . constructional features of telescopic gauges . parts of a small hole gauge Telescopic gauges are popular for fine work as they are very rigid and have a better 'feel'. Uses Used for measuring the sizes of holes, slots and recesses. Construction Telescopic gauges are 'T' shaped. They consist of a pair of telescopic legs or plungers connected to a handle. The plungers are spring loaded to force them apart. After inserting the gauge in a hole or slot, it can be locked in position by turning the knurled handle. It may then be withdraw from the hole and measured with a micrometer. Telescopic gauges are available in a set of 5 nos, to measure holes from 12.7mm to 152.4mm. No.1 12.7mm to 19mm No.2 19.0mm to 31.7mm No.3 31.7mm to 53.9mm No.4 53.9mm to 88.9mm No.5 88.9mm to 152.4mm Small hole gauges Telescopic gauges are not suitable for measuring holes below 12.7mm. For measuring smaller holes and slots, small hole gauges are used. Construction A...